This invention relates to a method of making a rotary engine internal fixed bearing surface and rotor for rotating about the fixed bearing surface.
A rotary engine obtains a number of clearances around bearings and gears required to effect eccentric rotation of its rotor. The increase in such clearances during the repeated operation of the engine prevents smooth eccentric rotation of the rotor, resulting in the apperance of disorder in the trochoidal curve followed by the rotor apexes. This disorder leads to development of wear and damage between the internal surface of the casing and the rotor apexes and leakage of gases through the gaps between the casing internal surface and the rotor apexes. It is, thus, imperative to construct such an engine with an increased gap between the casing internal surface and the rotor apexes to make up for the width of such disorder in the trochiodal curve. No sealing material so far used is satisfactory for the purpose of closing such an enlarged gap against gas leakage, but the rotary engines known in the art operate with a poor combustion efficiency.
This invention has been made with a view to eliminating the aforementioned drawbacks of the rotary engines known in the art. According to this invention, there is provided a method of constructing a rotary engine in which only a single bearing is involved to effect eccentric rotation of its rotor of which the apexes follow a trochiodally curved path during the rotor roation, and in which the single bearing is ensured against any disorder in the bearing support for the rotor while the latter is rotating. This invention provides a method of constructing a rotary engine, and more particularly, a novel and improved method of formulating the elliptical cross-sectional configuration of a supporting shaft secured to sideboards and the regular triangular configuration of a rotor bearing which cooperate to permit smooth eccentric rotation of the rotor without causing any leakage developing disorder. The method of this invention ensures construction of such an elliptical configuration which represents a geometrically reasonable and perfect shape permitting the elliptical supporting shaft to be maintained in sliding contact with the internal surface of the triangular bearing without leaving or being caught in such internal bearing surface at any moment throughout the rotation of the shaft relative to the bearing surface. There is, thus, practically no clearance between those elliptical and triangular surfaces. Therefore, no undesirable disorder can develop in the cooperative rotation of the elliptical shaft and the triangular bearing, however long such rotation may continue.
In the most typical rotary engine known in the art as the NSU-Wankel engine, the rotor within the casing achieves eccentric revolution around an eccentric shaft and during such revolution, it also rotates about its own axis of rotation by virtue of the cooperation between an externally toothed stationary gear and an internally toothed movable gear. Undesirable clearances or excessive play appears between the eccentric shaft and main and rotor bearings, while backlash and incorrect tooth engagement appear between the stationary and movable gears. These clearances, play and incorrect engagement may develop to prevent smooth eccentric rotation of thr rotor, resulting in disorder in the trochiodal curve following by the rotor apexes.
U.S. Pat. No. 3,884,600 to Gray describes a rotary engine in which the eccentric rotation of a rotor is accomplished by the cooperation of an elliptical guide member in the center of an end plate and a regular triangular bearing surface on one side of the rotor. In Gray's engine, however, the bearing surface on the rotor rotates about the guide member on the end plate. During a full rotation of the bearing surface, the elliptical guide member is contacted by all the three sides of the triangular bearing surface, or separated from at least one of the sides of the triangular bearing surface, so that excessive clearances or play develop between the rotor and the bearing surface. Gray himself points out this problem in the specification of his United States patent. Gray clearly reveals the aforementioned disadvantages in FIG. 3 accompanying his patent. In his specification, Gray fails to discover a geometrically reasonable and perfect elliptical configuration which permits the guide member to be maintained in smooth sliding contact with the triangular bearing surface for rotation relative thereto without separating from or being hindered by the bearing surface. In Gray's rotary engine, the rotor fails to achieve smooth eccentric rotation within the casing, with a resultant disorder in the trochoidal curve followed by the rotor apexes.
In both Wankel and Gray engines, as discussed above, disorder appears in the trochoidal curve followed by the rotor apexes and gives rise to undesirable wear and damage between the casing internal surface and the rotor apexes, as well as leakage on the gas-tight chamber. Therefore, it has heretofore been essential to construct an engine with an enlarged clearance between the casing internal surface and the rotor apexes to compensate the width of such disorder in the trochoidal curve. Such a clearance is, however, too large to be effectively closed against leakage; and the engine has only a poor combustion efficiency.